/*********************************************************************************
This code is provided for internal research and development purposes by Huawei solely,
in accordance with the terms and conditions of the research collaboration agreement of May 7, 2020.
Any further use for commercial purposes is subject to a written agreement.
 *  OKVIS - Open Keyframe-based Visual-Inertial SLAM
 *  Copyright (c) 2015, Autonomous Systems Lab / ETH Zurich
 *  Copyright (c) 2016, ETH Zurich, Wyss Zurich, Zurich Eye
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 * 
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 *   * Neither the name of Autonomous Systems Lab / ETH Zurich nor the names of
 *     its contributors may be used to endorse or promote products derived from
 *     this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 *
 *  Created on: Sep 12, 2013
 *      Author: Stefan Leutenegger (s.leutenegger@imperial.ac.uk)
 *    Modified: Zurich Eye
 *********************************************************************************/

/**
 * @file ErrorInterface.hpp
 * @brief Header file for the ErrorInterface class. A simple interface class that
          other error classes should inherit from.
 * @author Stefan Leutenegger
 */

#pragma once

#include <Eigen/Core>

namespace ze {

namespace nlls {

/// @brief Simple interface class the errors implemented here should inherit from.
class ErrorInterface
{
 public:
  EIGEN_MAKE_ALIGNED_OPERATOR_NEW

  /// @brief Constructor
  ErrorInterface() = default;
  /// @brief Destructor (does nothing).
  virtual ~ErrorInterface() = default;

  /// @name Sizes
  /// @{

  /// @brief Get dimension of residuals.
  /// @return The residual dimension.
  virtual size_t residualDim() const = 0;

  /// @brief Get the number of parameter blocks this is connected to.
  /// @return The number of parameter blocks.
  virtual size_t parameterBlocks() const = 0;

  /**
   * @brief get the dimension of a parameter block this is connected to.
   * @param parameter_block_idx The index of the parameter block of interest.
   * @return Its dimension.
   */
  virtual size_t parameterBlockDim(size_t parameter_block_idx) const = 0;

  /// @}
  // Error and Jacobian computation
  /**
   * @brief This evaluates the error term and additionally computes
   *        the Jacobians in the minimal internal representation.
   * @param parameters Pointer to the parameters (see ceres)
   * @param residuals Pointer to the residual vector (see ceres)
   * @param jacobians Pointer to the Jacobians (see ceres)
   * @param jacobians_minimal Pointer to the minimal Jacobians (equivalent to jacobians).
   * @return Success of the evaluation.
   */
  virtual bool EvaluateWithMinimalJacobians(
      double const* const * parameters, double* residuals, double** jacobians,
      double** jacobians_minimal) const = 0;

  /// @brief Residual block type as string
  virtual std::string typeInfo() const = 0;
};

}  // namespace nlls
}  // namespace ze
